The invention relates to a mobile radio apparatus for a motor vehicle that has two mobile radio modules that can be used to interchange a mobile radio signal with an external mobile radio station. The invention also relates to a motor vehicle having such a mobile radio apparatus and to a method for operating the mobile radio apparatus.
A mobile radio module in such a motor vehicle can allow telephone calls to be made using the mobile radio network of a mobile radio operator from a telephone in the motor vehicle. The term motor vehicle is understood to mean, for example, an automobile or a heavy goods vehicle. Such a mobile radio module usually comprises one or more integrated circuits (computer chip) that take the digital data that is to be sent and produce a mobile radio signal that can be output via a signal connection to an antenna so as to be sent therefrom to a mobile radio station. Conversely, a mobile radio signal received from such a mobile radio station can be processed by the mobile radio module in order thus to extract the voice data that the mobile radio signal contains. Besides telephony, such a mobile radio link can also be used to transmit digital useful data of another type, particularly network data for data interchange with the Internet, that is to say e-mails or browser data, for example.
With the advancing development of mobile radio technology, a motor vehicle needs to ensure that the mobile radio apparatus installed therein can also communicate with the mobile radio stations of different mobile radio standards. To this end, it is known practice, for example, to provide a mobile radio module in a mobile radio apparatus, designed for transmission on the basis of the GSM standard (global system for mobile communications) or for signal transmission on the basis of the UMTS standard (UMTS—universal mobile telecommunication system). Data transmission between the motor vehicles and a mobile radio network then takes place in each case via that mobile radio module for which a suitable mobile radio station is available in the surroundings of the motor vehicle.
In connection with multipath reception of mobile radio signals, it is known practice for two or more antennas to be provided in a motor vehicle.
When developing a motor vehicle, it must be borne in mind, in connection with the provision of mobile radio apparatuses for new telecommunication standards, that such new standards do not always work reliably in the first few years following introduction. By way of example, in the case of the new LTE standard (LTE—long term evolution), the envisaged transmission type for telephony VoLTE is not yet supported by the mobile radio networks. Instead, it is necessary to revert to an earlier standard, for example UMTS or GSM. On the basis of experience, the implementation of LTE in motor vehicles will therefore involve technical difficulties, which means that it is desirable to have a redundant fallback solution.